From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6022A1F955 for ; Tue, 1 Aug 2023 09:26:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBB77C433C7; Tue, 1 Aug 2023 09:26:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690881998; bh=5OuVzdwn1BQzTT9FwN4c1HtEgiOsoCPh1mGjqBIGJMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b5abTMP4i9UbgmtUK69Q3VLmvTMX52QkfVKThRFtV2xjb39LSPQUmAsWRFl1vZSG8 xwUENE/GbbKMfbR4ZfNfG2vd9mFm31DyFDnv05Avj2ZH0y6AV/V5ISpKkT7DgFMaAn sMthePuEv/RF9JE8ELepI1CwGPkc/Ma6w6Dx4FqM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zheng Zhang , Kees Cook , Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.15 104/155] KVM: Grab a reference to KVM for VM and vCPU stats file descriptors Date: Tue, 1 Aug 2023 11:20:16 +0200 Message-ID: <20230801091913.951630144@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230801091910.165050260@linuxfoundation.org> References: <20230801091910.165050260@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Sean Christopherson commit eed3013faa401aae662398709410a59bb0646e32 upstream. Grab a reference to KVM prior to installing VM and vCPU stats file descriptors to ensure the underlying VM and vCPU objects are not freed until the last reference to any and all stats fds are dropped. Note, the stats paths manually invoke fd_install() and so don't need to grab a reference before creating the file. Fixes: ce55c049459c ("KVM: stats: Support binary stats retrieval for a VCPU") Fixes: fcfe1baeddbf ("KVM: stats: Support binary stats retrieval for a VM") Reported-by: Zheng Zhang Closes: https://lore.kernel.org/all/CAC_GQSr3xzZaeZt85k_RCBd5kfiOve8qXo7a81Cq53LuVQ5r=Q@mail.gmail.com Cc: stable@vger.kernel.org Cc: Kees Cook Signed-off-by: Sean Christopherson Reviewed-by: Kees Cook Message-Id: <20230711230131.648752-2-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- virt/kvm/kvm_main.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3804,8 +3804,17 @@ static ssize_t kvm_vcpu_stats_read(struc sizeof(vcpu->stat), user_buffer, size, offset); } +static int kvm_vcpu_stats_release(struct inode *inode, struct file *file) +{ + struct kvm_vcpu *vcpu = file->private_data; + + kvm_put_kvm(vcpu->kvm); + return 0; +} + static const struct file_operations kvm_vcpu_stats_fops = { .read = kvm_vcpu_stats_read, + .release = kvm_vcpu_stats_release, .llseek = noop_llseek, }; @@ -3826,6 +3835,9 @@ static int kvm_vcpu_ioctl_get_stats_fd(s put_unused_fd(fd); return PTR_ERR(file); } + + kvm_get_kvm(vcpu->kvm); + file->f_mode |= FMODE_PREAD; fd_install(fd, file); @@ -4409,8 +4421,17 @@ static ssize_t kvm_vm_stats_read(struct sizeof(kvm->stat), user_buffer, size, offset); } +static int kvm_vm_stats_release(struct inode *inode, struct file *file) +{ + struct kvm *kvm = file->private_data; + + kvm_put_kvm(kvm); + return 0; +} + static const struct file_operations kvm_vm_stats_fops = { .read = kvm_vm_stats_read, + .release = kvm_vm_stats_release, .llseek = noop_llseek, }; @@ -4429,6 +4450,9 @@ static int kvm_vm_ioctl_get_stats_fd(str put_unused_fd(fd); return PTR_ERR(file); } + + kvm_get_kvm(kvm); + file->f_mode |= FMODE_PREAD; fd_install(fd, file);